Python version 3.10 breaks the application

[chovanecadam]

Hello, the application attempts to import Mapping from collections and fails to run:

ImportError: cannot import name 'Mapping' from 'collections' (/usr/lib64/python3.10/collections/__init__.py)

This is due to a change in Python3.10:

Remove deprecated aliases to [Collections Abstract Base Classes](https://docs.python.org/3/library/collections.abc.html#collections-abstract-base-classes) from the [collections](https://docs.python.org/3/library/collections.html#module-collections) module. (Contributed by Victor Stinner in [bpo-37324](https://bugs.python.org/issue?@action=redirect&bpo=37324).)

The docker container works without any issues. Could we add this constraint about the Python version to the readme file?

[dolevf]

Thank you for submitting this.

[dolevf]

https://github.com/dolevf/Damn-Vulnerable-GraphQL-Application/blob/master/README.md